Rod about to blow? Kawasaki

I hope that some one might be able to offer some insight.
I have a 12.5 HP Kawasaki engine that is on a 36" John Deere commercial walkbehind lawn mower. The age of the engine is unknown, maybe 7 years old? I have noticed that some thing is trying to break out of the aluminum Engine case. There is a tear or puncture begining and it seems to extend 1/4 of an inch.
The tear is located at the true back side tword the operator or transmission. The engine starts and runs well. Motor does run a little high on RPM. All insite and ideas are welcome.

I don't think this is a problem since there is no noise being made and it runs fine. Maybe the casting is rough there and you just noticed it? Maybe it was there from a previous rod blow? Do you see a weld or epoxy there as a repair? If aluminum bulges out 1/4 on an inch it should be leaking oil also. Let me know.

Khouse,
Thank you for your prompt response to the question asked.
Although the engine is running high, there is no unusual noise. It might have always been there. This seems to be a crack and it extends 1/2 an inch and seems to begin to opening outward. This crack has not yet opened. Maybe open is not the correct word. It is still a crack busting out from the inside. There is no sign of oil coming out. No sign of a weld or epoxy repair. I will adjust the throttle and run it until it gives out.

Just a thought! A friend of mine had a situation the same as yours. He took it to the shop and they found that he had left the mower outside in the rain and water had gotten into the crank case. That winter the water froze up and caused a swell and crack in the thin area of the crankcase. He noticed the water in the oil that spring and changed the oil. He ran the mower a month before he noticed the crack and took it to the shop. It does not leak oil and still runs fine. Maybe it is a cold weather crack?